1. Field of Invention
The present invention relates to a display apparatus using a projection liquid crystal display device. More specifically, the present invention relates to a display apparatus having two types of display modes. Furthermore, the present invention relates to an information display system using the display apparatus.
2. Description of Related Art
In various types of display apparatuses that have been proposed, one unit of a projection liquid crystal display device in which light optically modulated by a liquid crystal device is enlarged and projected onto a display plane can exhibit images to many viewers since the display plane is large. In particular, according to a projection display device, a so-called xe2x80x9crear projectorxe2x80x9d, in which optically modulated light is enlarged and projected from the back side of the display plane, since all of optical systems can be disposed on the back side of the display plane, further utilization of the device as an advertising medium can be anticipated.
According to the projection display device (rear projector), however, since light is projected from the back side of the display plane, there is a problem in that an image becomes difficult to see by reflection of external light when external light shines on the surface of the display plane.
As a typical example of advertising media, a signboard is most common. However, the signboard can only display fixed information; it cannot display moving pictures or the like. In addition, redoing of the displayed content requires much labor and time.
Accordingly, it is an object of the present invention to at least provide a display device which can switch a display mode according to the environment, such as that of the day and night.
According to a first exemplary aspect of the present invention, there is provided a display apparatus which may include: a projection display device for enlarging and displaying an image from the back side of a display plane, a screen disposed on the front side of the display plane of the projection display device, and a screen driving device for moving the screen to thereby switch between a first state where the display plane of the projection display device is covered with the screen and a second state where the display plane of the projection display device is visible from the front.
In this exemplary embodiment of the present invention, since the display plane of the projection display device is covered with the screen in the first state, information provided at the front face of the screen is displayed using the screen as a signboard. In contrast, since the screen is moved and the display plane of the projection display device is in a visible state in the second state, information is displayed by the projection display device. For this reason, if the first state is set in the daytime and the second state is set in the nighttime, a display mode can be switched according to surrounding conditions such that the function of the projection display device is exhibited to the fullest extent in the nighttime in which there is no effect of external light, and in the daytime in which display is affected by the external light, display is performed by the screen which is not affected by the external light. In addition, while the information provided on the screen cannot be as easily as redone as in a signboard, the information displayed by the projection display device can be easily redone if an image signal is changed. Therefore, an advertisement and a guide, which are displayed for a considerably long time, may be displayed using the screen, and information, which is frequently redone, such as event information, may be displayed using the projection display device. In addition, while the screen can display only a fixed image, the projection display device can also display moving images as in a manner similar to that of a television. In this way, the most suitable display mode can be selected from the viewpoints of the type of information to be displayed, the changing cycle of information, etc.
In another exemplary embodiment of the present invention, the projection display device may include, for example, a light source, a liquid crystal device for modulating light emitted from the light source, and a projection optical system for enlarging and projecting light modulated by the liquid crystal device onto the back side of the display plane.
In another exemplary embodiment of the present invention, when the screen has a belt-like shape extending in a moving direction of the screen, the belt-like screen may be preferably formed with a light transmission window for enabling the display plane of the projection display device to be visible in the second state.
In another exemplary embodiment of the present invention, the screen driving device may include, for example, a pair of rollers for winding up and paying out the screen, and a roller driving device for rotatably driving the pair of rollers to switch the position of the screen between the first state and the second state.
In another exemplary embodiment of the present invention, it is preferable that a plurality of information be provided at the front side of the screen in the longitudinal direction of the screen, and the screen driving device intermittently drives the screen in the first state to thereby display the plurality of information by the screen while switching.
In another exemplary embodiment of the present invention, the screen driving device may preferably include, for example, a drive control section for placing the position of the screen in the first state in the daytime, and for placing the position of the screen in the second state in the nighttime.
According to another exemplary aspect of the present invention, there is provided a display apparatus which may include: a projection display device having a display screen, a first roller part disposed on a first side surface of the projection display device, a second roller part disposed on a second side surface of the projection display device opposing the first side surface, a screen disposed along a display screen with one end attached to the first roller part and the other end attached to the second roller part, a projection part provided on the screen for enabling a displayed image from the projection display device to be visible, and an information area formed on the screen.
According to the arrangements, since the screen can be disposed along the side surface of the projection display device, the size of the display apparatus can be reduced.
In another exemplary embodiment of the present invention, the display apparatus may further include a drive control section for controlling the rotation of the first roller part and the second roller part and for moving the screen.
Furthermore, in another exemplary embodiment of the present invention, the drive control section has a time control part, and moves the screen when a predetermined time is reached.
According to this arrangement, information, such as an advertisement or the like, displayed by the screen and the projection display device can be provided based on the set time.
In another exemplary embodiment of the present invention, the screen is detachable with respect to the projection display device.
According to this arrangement, information, such as an advertisement or the like, can be easily replaced.
In another exemplary embodiment of the present invention, the projection part of the screen is a window for exposing a display screen of the projection display device.
In another exemplary embodiment of the present invention, the projection part of the screen projects a displayed image of the projection display device onto the screen.
In another exemplary embodiment of the present invention, the display apparatus may further include a stretching part for stretching the screen at least on both sides of the projection part of the screen.
With this arrangement, since at least the projection part of the screen onto which an image is projected can be prevented from being distorted, a good image can be projected onto the screen.
According to another exemplary aspect of the invention, there is provided an information display system, including: a projection display device having a display section, a display apparatus disposed along the display section of the projection display device and having at least one image area and a screen including a display area for enabling displayed information from the projection display device to be visible, and an information supply section for transmitting displayed information to the display device.
According to the arrangements, information can be provided to a plurality of display apparatuses from one information supply section.
In another exemplary embodiment of the present invention, the display apparatus and the information supply section communicate information bidirectionally via lines.
According to this arrangement, information can be exchanged bidirectionally between the display apparatus and the information supply section, making it possible to hold a specific condition of the display apparatus.
In another exemplary embodiment of the present invention, the display apparatus has a self-check function, and transmits abnormal information of the display apparatus to the information supply section when an abnormality is determined.
According to this arrangement, an abnormality of the display device can be found, making it possible to efficiently check the display apparatus.